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Helis and fixed wing

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Saturday, September 23, 2017

MX-Bach "Sorta 2" Is Flight Ready!

So last night was busy. but this morning I focused and finished reinstalling the electronics and wiring harness for the MX-Bach.


Sweet. The airflow in the fuse is so high that the fan is trite, but I love it! I had to program the ESC using the Transmitter and tones, and it worked out pretty well. Usually the tones go so fast its hard to keep track of where I am in the schema, but this one was easy. I had already ordered the ESC Programming box earlier this morning... oh well. Her default was heli-governed with a slow start.




She came in at 14 lbs AUW with 2 5S 4500 mAh Power packs in series, and the 2S 4000 mAh Receiver pack. The original MX2 was supposed to be 11 lbs....  I don't remember what she weighed before, but I really did not add much weight.



I used a programming trick Spektrum taught me to set up the dual elevators in the radio (using Elevator and Mix #5 set to the Gear Channel), and they are spot on. I set her up with flaperons for fun. Yeah, those are vortex generators on the wing ends. She liked to drop a wing in stall, so when I was looking for a candidate to play with the generators, I chose her, and they work really well, lowering her no flap and flap stall speeds noticeably.





Power tested, produced 13.6 lbs static thrust at full throttle, almost 1:1, great for a sport flier, and ran for 14 min to 3.6 V a cell at half throttle without beginning to slow. (The ESC Voltage Sensor senses the 2S pack, not the 2 5S packs; probably because the ESC plug is in the Receiver, powered by the 2S? Not sure. It had ran for about 10 min when I realized this, and decided to see how far they would go. At 14 min I figured that was enough...). I set the timer to 8 min. I like 2 min Bingo Fuel, so after I see what she leaves in the tank on the first flights, I may increase  to 10 min.

I am not sure about the CG. There is some weight change with the 2S pack (I think I used a smaller one before, maybe 1500?), its location (before it was set sideways across the fuse), but its pretty much centered in the same place as the old pack. There is a smidge weight addition with the new ESC too. I use the wing tube as the CG and she looks about right, maybe a touch nose heavy. We'll see. Hoping to fly her tomorrow!

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